Re: This seems like a good argument for ion drives

Dawn had ion engine for trajectory changes.

What I'm curious about is whether it also has reaction wheels or similar for attitude control, whether those had also failed.

It would also be interesting to know what kind of spool-up spool-down delays, if any, ion drives have, and how much efficiency is lost during that time.. and if they could be made small enough to be used for attitude control. You'd need 8-16 of them.

Re: But why were the transmitters shut down?

If dead probes weren't shut down, you'd eventually have no frequencies left for new probes to transmit on. So they shut it off, while it's antennas were still pointing close enough towards earth to be able to receive commands.

A US navy navigation satellite launched in 1964 still wakes up occasionally when it gets sunlight on its panels, and transmits telemetry. At its job of navigation satellite it failed 2 months after launch.

Iirc, Apollo era fault detection, and probably Soyuz too, consists of a long piece of wire that runs up and down the length of the rocket. If the rocket goes boom, the wire is broken, which triggers abort.

Then it's a question of how fast explosive bolts and the abort motor light up after being lit up. Hopefully fast enough that the fireball shockwave still hasn't reached the crew.

Re: Forget the geeky stuff, sort out the user experience.

From my observations of random people trying gimp, they can't find anything because the buttons are all in windows floating around, sometimes with scrollbars, sometimes not.

Then, eventually, they try close gimp, except most of the time they close all the toolboxes before closing whichever window that makes gimp actually close. On next start, all the toolbox windows are gone, and user wonders where everything went, or concludes that maybe he/she misremembered and that gimp actually has no features.

Re: Good news, everyone!

Hand a laptop or phone manufacturer a battery twice as good as their current batteries, and their next device will have a battery half the size of their previous device. Marketing will be hyping the thin sleek design, and everyone will still be whining about how battery technology isn't keeping up.

Re: Replacing the batteries.

The different range options on a Tesla actually uses the same physical battery, the software limitations are just different. Now then, why does it cost more to be allowed to use more of the battery's capacity? Because using less makes it last longer and lowers Tesla's warranty repair costs.

When it comes to phones, the phone manufacturers crank the settings all the way to the "maximum capacity, some explosions, short life" end of the scale. And sometimes a bit too far.

From a northerly Scandinavian perspective, the bicyclist was out in the dark without wearing reflectors on her person, her bike was lacking basic side reflectors, and the legally mandated front light was not present or working at the required level. Crossing that road seems dubious at best, and I wonder how the bicyclist didn't notice the uber's headlights when, presumably, looking to both sides and listening for cars before crossing the road. The road could use fencing in the middle to prevent crossing by moose and pedestrians, except for designated moose and/or pedestrian crossings.

The only cars I've seen have 14.5V regulated alternator, that if you're lucky is temperature compensated. Low voltage protection doesn't exist, but sometimes happens accidentally because the starter solenoid just drops out when voltage collapses. Some fancier fuel burning heaters with timers do have low voltage cutoffs, though.

Re: Handbrake users beware

Where, if the read and write are implemented as sending big requests to the kernel, should be minimally affected. The processing portion of it is surely 99% of the whole processing time anyway?

I could believe things like a database would slow down, when it's hopping all over the place on disk looking for/writing data. I could believe facebook slows down alot, because browsers are doing lots of itsy bitsy tiny reads and writes to both disk and net, and lots of small updates of the screen to animate all the gifs and what not.

Re: Lots of testing work to be done then?

It's the move to and from kernel that is penalized, time spent inside kernel and time spent outside kernel isn't penalized. Of course, hardly any system monitoring programs will tell you how many syscalls or context switches different programs cause.

Re: "To provide a better experience to customers"

What's preferable, phone unexpectedly shutting down without warning, or phone slowing down to avoid sudden shutdown?

The big issue is of course that the user wasn't notified in either case, on any brand of phone (androids also suffer from thus when their battery gets old, sudden shutdowns despite having 30% left).

On the other hand, it's not an easy problem to solve. Unexpected shutdown means unexpected, even if there was an algorithm trying to collect data about the operating state of the cpu and all its peripherals, and recording battery voltages, when unexpected shutdown hits you lose the data. The hardware shuts down to protect both the battery (since they become unstable from operating at low voltage) and the CPU, ram and storage from corrupting data due to insufficient voltage.

AMD have a "clock stretching" feature in some of their CPUs, if the voltage inside the CPU drops the frequency slows down. It's mostly meant to allow them to operate with lower voltages and save power by not needing as big "safety margin" in voltage. Would be interesting to see something similar in mobile SOCs!

It's kinda remarkable that battery meters are still so bad at tracking the capabilities of an aging battery. On one hand, it's a kinda neglected area where manufacturers choose the cheapest component. On the other hand, it's a difficult problem! Batteries aged in standard cycle testing behave differently to batteries aged in real life. Batteries in real life age differently depending on how they're used and charged.

What do I mean by aged differently? As is well known, a battery's voltage sags when you put a load on it. The bigger the load, the more the voltage drops. The amount of drop is, for most part, a linear function of the load. When the battery is new, the sag is so small it makes no difference. The amount of sag can be described as internal resistance. More internal resistance means more sag.

On a new battery, the internal resistance stays nearly constant regardless if the battery is 100% or 20% full. Towards empty it becomes a bit higher. With an ideally cycled and aged battery, the capacity is lower, and the internal resistance is higher, but the internal resistance is still around the same order of magnitude regardless the battery is full or empty.

With batteries aged in real life conditions, where the battery might've spent a lot of time at 100%, a lot of time at 0%, a lot of time in heat, etc, the results on internal resistance will be different. The internal resistance might sharply rise as the battery discharges. From the initial situation with a fresh battery having a flat internal resistance curve vs state of charge, to having a inclined straight line describing an increased resistance at empty, to having exponentially increasing resistance towards empty.

Why does this all matter? Because currently there's no battery meter chip that can take into account anything except the "internal resistance is the same regardless of how full battery is" situation. Most chips don't account for internal resistance at all.

So from an engineer's perspective, if Apple is actually tracking actual battery performance and managing to make their system adapt to having a smaller and smaller power budget, that's kinda impressive. Makes me glad someone is finally paying attention to adding more sophistication to battery management systems!

Of course, they could just have put in a battery twice as big and they wouldn't have had issues with shrinking power budget for the phone's "lifetime", and they wouldn't need to consider aging battery.

Re: Battery shape?

It's more like, the more you focus on a battery's ability to deliver high peak power, then more you take away from its ability to to store energy. It's a tradeoff. Mobile phones very much favour capacity over power, Apple perhaps more so than the rest. Also keeping in mind that Apple has very powerful CPU while at the same time having "unremarkable" battery capacity, in remarkably small space, it pushes everything to the limit.

In this case they pushed it perhaps too far, when some batteries have aged a bit too fast.

Re: $20 per transaction fee

I remember back in the day when some nerds were trying to explain the usefulness of bitcoin, they argued speed of transaction and cost of transactions as superior to regular banking. At the time I thought the argument was dubious at best, as bank transactions were on the order of minutes, and transactions usually included with other services anyway, costing nothing extra.

"But bitcoin isn't vulnerable to the whims of governments and central bankers!" - well sure, but is the whims of the collective speculative investor hivebrain any better?

I think the biggest issue is the sheer number of passwords required. The average person probably struggles to remember more than 2 "difficult" passwords. Add to that, that every little thing wants you to make a user account and password, so you end up with hundreds.

Laser altimeter is the kind of thing a hobbyist would use, since hobbyist radars make ofcom/FCC/etc annoyed. GPS and barometric sensors aren't that good for approaching the ground at a ensured survivable rate.

Re: planet is surrounded by spy satellites

The spy satellites are more concerned with photographing military targets. Even so, had they been tasked with photographing the ocean, you would've needed quite some luck to have taken a picture of the right area before the debris got scattered out blending in with all the other debris floating around.. Not to mention the manpower needed to sift through all those photos. There was a crowd sources effort to look through satellite photos, which turned up empty.

On mine it "upgrades" the synaptics touchpad drivers to a version which turns the touchpad on and off rapidly. The blinking notification onscreen (at around 20 on/off cycles per second) is annoying enough, it also makes it harder to click things so I can roll back to the working version.

Re: Not applicable in any place I lived...

There are battery powered electronic versions of that valve, including ones with wireless control through a central "router", and the facepalm quality mobile apps. I know one manufacturer already deprecated their first gen versions of this, leaving expensive systems vulnerable. I'm looking at you, Danfoss.

I wonder what the outcome would've been if they instead had heavily optimized the engine to run the cleanest at exactly the test regime conditions, but provide increased power and higher emissions when the driver pushes the throttle and deviates from the teat conditions?

It would on one hand be a sort if cheat, but on the other hand one could argue that it would be reasonable for the test, that the authorities designed, to reflect the most common expected use, and that it made sense to optimize the engine for these conditions...

I myself tend to use the style which BMW (iirc) found to be most efficient, pedal to the floor, shift up before 2000rpm until in highest gear.

Re: Lithium batteries are last century's technology

There are phones with large batteries available. Hardly anyone buys them. Thus, battery capacity stays low on most other models. What's the point making phone with big battery when everyone is fine with 8hour life?

2 year life

According to the article, FP1 was still sold in 2015. It is now 2017, and the device is unsupported. If someone had bought it on a 2 year contract from an operator in late 2015, it might've entered unsupported status before the customer had even paid it off! Not to mention statutory warranty periods..